304.
See the web page
/
or
/
.
305.
See the web page
/
.
306.
See the web page
.
307.
See the web page
.
308.
‘‘The Muon Anomalous Magnetic Moment: A Harbinger for ‘New
Physics’,’’ A. Czarnecki and W. J. Marciano, Phys. Rev. D
64
,
013104
~
2001
!
.
~
A
!
C. Plans for future facilities
The particle physics community is developing a number of
options to probe further beyond the standard model. These
include a large linear
e
1
e
2
collider, intense sources of neu-
trinos
~
‘‘neutrino factories’’
!
, a muon collider, and a Very
Large Hadron Collider
~
VLHC
!
with energy significantly
greater than the LHC. Descriptions of all of these options
may be found in the Proceedings of the 2001 Snowmass
Workshop.
309
309.
Proceedings of the APS/DPF/DPB Summer Study on the Future of
Particle Physics
~
Snowmass 2001
!
, Snowmass, Colorado, 30
June–21 July 2001, eConf C010630
~
2001
!
.
XIII. SUMMARY
The standard model of electroweak and strong interactions
has been in place for nearly thirty years, but precise tests
have entered a phase that permits glimpses of physics be-
yond this impressive structure, most likely associated with
the yet-to-be discovered Higgs boson and certainly associ-
ated with new scales for neutrino masses. Studies of CP vio-
lation in decays of neutral kaons or
B
mesons are attaining
impressive accuracy as well, and could yield cracks in the
standard model at any time. It is time to ask what lies behind
the pattern of fermion masses and mixings. This is an
input
to the standard model, characterized by many free param-
eters all of which await explanation.
Many avenues exist for exploration beyond the standard
model, both theoretical and experimental. A lively dialogue
between the two approaches must be maintained, with ad-
equate support for each, if we are to take the next step in this
exciting adventure.
ACKNOWLEDGMENTS
I wish to thank T. Andre´ , T. Appelquist, R. Cahn, Z. Luo,
C. Quigg, G. Passarino, R. Shrock, R. Stuewer, O. L.
Weaver, and B. Winstein for constructive comments on the
paper, and the Theory Group at Fermilab for hospitality. This
work was supported in part by the United States Department
of Energy through Grant No. DE FG02 90ER40560.
318
318
Am. J. Phys., Vol. 71, No. 4, April 2003
Jonathan L. Rosner
